Home
Back
Ka From Pka Equation:
| From: | To: |
Ka (acid dissociation constant) and pKa are fundamental concepts in chemistry that describe the strength of acids. pKa is the negative logarithm of Ka, providing a more convenient scale for comparing acid strengths.
The calculator uses the mathematical relationship between Ka and pKa:
Where:
Explanation: This equation converts the logarithmic pKa scale back to the linear Ka scale, allowing direct calculation of the acid dissociation constant.
Details: Knowing Ka values is crucial for predicting acid-base behavior, calculating pH of solutions, understanding buffer systems, and designing chemical processes in pharmaceuticals and industrial chemistry.
Tips: Enter the pKa value as a numerical value. The calculator will compute the corresponding Ka value in mol/L. pKa values typically range from -10 to 50 for common acids.
Q1: What is the relationship between Ka and acid strength?
A: Larger Ka values indicate stronger acids, as they dissociate more completely in water. Smaller Ka values indicate weaker acids.
Q2: Why use pKa instead of Ka?
A: pKa provides a more convenient scale that compresses the wide range of Ka values (10^-10 to 10^10) into a manageable range of -10 to 10, making comparisons easier.
Q3: What are typical pKa values for common acids?
A: Strong acids have negative pKa values, weak organic acids typically range from 2-5, and very weak acids can have pKa values above 10.
Q4: How does temperature affect Ka values?
A: Ka values are temperature-dependent. The dissociation constant typically changes with temperature, so pKa values should be specified at a particular temperature (usually 25°C).
Q5: Can this calculator be used for bases?
A: For conjugate acid-base pairs, pKa + pKb = 14 (in water at 25°C), so you can calculate Kb from pKa of the conjugate acid.